content: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
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  //
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  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
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  // in the documentation and/or other materials provided with the
  // distribution.
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  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
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  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  package com.google.protobuf;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.EOFException;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.OutputStream;
  import java.io.UnsupportedEncodingException;
  import java.nio.ByteBuffer;
  import java.util.Arrays;
  import java.util.List;
  import java.util.NoSuchElementException;
  import junit.framework.TestCase;
  
  /**
   * Test {@code LiteralByteString} by setting up a reference string in {@link #setUp()}.
   * This class is designed to be extended for testing extensions of {@code LiteralByteString}
   * such as {@code BoundedByteString}, see {@link BoundedByteStringTest}.
   *
   * @author carlanton@google.com (Carl Haverl)
   */
  public class LiteralByteStringTest extends TestCase {
    protected static final String UTF_8 = "UTF-8";
  
    protected String classUnderTest;
    protected byte[] referenceBytes;
    protected ByteString stringUnderTest;
    protected int expectedHashCode;
  
    @Override
    protected void setUp() throws Exception {
      classUnderTest = "LiteralByteString";
      referenceBytes = ByteStringTest.getTestBytes(1234, 11337766L);
      stringUnderTest = ByteString.copyFrom(referenceBytes);
      expectedHashCode = 331161852;
    }
  
    public void testExpectedType() {
      String actualClassName = getActualClassName(stringUnderTest);
      assertEquals(classUnderTest + " should match type exactly", classUnderTest, actualClassName);
    }
  
    protected String getActualClassName(Object object) {
      return object.getClass().getSimpleName();
    }
  
    public void testByteAt() {
      boolean stillEqual = true;
      for (int i = 0; stillEqual && i < referenceBytes.length; ++i) {
        stillEqual = (referenceBytes[i] == stringUnderTest.byteAt(i));
      }
      assertTrue(classUnderTest + " must capture the right bytes", stillEqual);
    }
  
    public void testByteIterator() {
      boolean stillEqual = true;
      ByteString.ByteIterator iter = stringUnderTest.iterator();
      for (int i = 0; stillEqual && i < referenceBytes.length; ++i) {
        stillEqual = (iter.hasNext() && referenceBytes[i] == iter.nextByte());
      }
      assertTrue(classUnderTest + " must capture the right bytes", stillEqual);
      assertFalse(classUnderTest + " must have exhausted the itertor", iter.hasNext());
  
      try {
        iter.nextByte();
        fail("Should have thrown an exception.");
      } catch (NoSuchElementException e) {
        // This is success
      }
    }
  
    public void testByteIterable() {
      boolean stillEqual = true;
      int j = 0;
      for (byte quantum : stringUnderTest) {
        stillEqual = (referenceBytes[j] == quantum);
        ++j;
      }
      assertTrue(classUnderTest + " must capture the right bytes as Bytes", stillEqual);
      assertEquals(classUnderTest + " iterable character count", referenceBytes.length, j);
    }
  
    public void testSize() {
      assertEquals(classUnderTest + " must have the expected size", referenceBytes.length,
          stringUnderTest.size());
    }
  
    public void testGetTreeDepth() {
      assertEquals(classUnderTest + " must have depth 0", 0, stringUnderTest.getTreeDepth());
    }
  
    public void testIsBalanced() {
      assertTrue(classUnderTest + " is technically balanced", stringUnderTest.isBalanced());
    }
  
    public void testCopyTo_ByteArrayOffsetLength() {
      int destinationOffset = 50;
      int length = 100;
      byte[] destination = new byte[destinationOffset + length];
      int sourceOffset = 213;
      stringUnderTest.copyTo(destination, sourceOffset, destinationOffset, length);
      boolean stillEqual = true;
      for (int i = 0; stillEqual && i < length; ++i) {
        stillEqual = referenceBytes[i + sourceOffset] == destination[i + destinationOffset];
      }
      assertTrue(classUnderTest + ".copyTo(4 arg) must give the expected bytes", stillEqual);
    }
  
    public void testCopyTo_ByteArrayOffsetLengthErrors() {
      int destinationOffset = 50;
      int length = 100;
      byte[] destination = new byte[destinationOffset + length];
  
      try {
        // Copy one too many bytes
        stringUnderTest.copyTo(destination, stringUnderTest.size() + 1 - length,
            destinationOffset, length);
        fail("Should have thrown an exception when copying too many bytes of a "
            + classUnderTest);
      } catch (IndexOutOfBoundsException expected) {
        // This is success
      }
  
      try {
        // Copy with illegal negative sourceOffset
        stringUnderTest.copyTo(destination, -1, destinationOffset, length);
        fail("Should have thrown an exception when given a negative sourceOffset in "
            + classUnderTest);
      } catch (IndexOutOfBoundsException expected) {
        // This is success
      }
  
      try {
        // Copy with illegal negative destinationOffset
        stringUnderTest.copyTo(destination, 0, -1, length);
        fail("Should have thrown an exception when given a negative destinationOffset in "
            + classUnderTest);
      } catch (IndexOutOfBoundsException expected) {
        // This is success
      }
  
      try {
        // Copy with illegal negative size
        stringUnderTest.copyTo(destination, 0, 0, -1);
        fail("Should have thrown an exception when given a negative size in "
            + classUnderTest);
      } catch (IndexOutOfBoundsException expected) {
        // This is success
      }
  
      try {
        // Copy with illegal too-large sourceOffset
        stringUnderTest.copyTo(destination, 2 * stringUnderTest.size(), 0, length);
        fail("Should have thrown an exception when the destinationOffset is too large in "
            + classUnderTest);
      } catch (IndexOutOfBoundsException expected) {
        // This is success
      }
  
      try {
        // Copy with illegal too-large destinationOffset
        stringUnderTest.copyTo(destination, 0, 2 * destination.length, length);
        fail("Should have thrown an exception when the destinationOffset is too large in "
            + classUnderTest);
      } catch (IndexOutOfBoundsException expected) {
        // This is success
      }
    }
  
    public void testCopyTo_ByteBuffer() {
      ByteBuffer myBuffer = ByteBuffer.allocate(referenceBytes.length);
      stringUnderTest.copyTo(myBuffer);
      assertTrue(classUnderTest + ".copyTo(ByteBuffer) must give back the same bytes",
          Arrays.equals(referenceBytes, myBuffer.array()));
    }
  
    public void testMarkSupported() {
      InputStream stream = stringUnderTest.newInput();
      assertTrue(classUnderTest + ".newInput() must support marking", stream.markSupported());
    }
  
    public void testMarkAndReset() throws IOException {
      int fraction = stringUnderTest.size() / 3;
  
      InputStream stream = stringUnderTest.newInput();
      stream.mark(stringUnderTest.size()); // First, mark() the end.
  
      skipFully(stream, fraction); // Skip a large fraction, but not all.
      int available = stream.available();
      assertTrue(
          classUnderTest + ": after skipping to the 'middle', half the bytes are available",
          (stringUnderTest.size() - fraction) == available);
      stream.reset();
  
      skipFully(stream, stringUnderTest.size()); // Skip to the end.
      available = stream.available();
      assertTrue(
          classUnderTest + ": after skipping to the end, no more bytes are available",
          0 == available);
    }
  
    /**
     * Discards {@code n} bytes of data from the input stream. This method
     * will block until the full amount has been skipped. Does not close the
     * stream.
     * <p>Copied from com.google.common.io.ByteStreams to avoid adding dependency.
     *
     * @param in the input stream to read from
     * @param n the number of bytes to skip
     * @throws EOFException if this stream reaches the end before skipping all
     *     the bytes
     * @throws IOException if an I/O error occurs, or the stream does not
     *     support skipping
     */
    static void skipFully(InputStream in, long n) throws IOException {
      long toSkip = n;
      while (n > 0) {
        long amt = in.skip(n);
        if (amt == 0) {
          // Force a blocking read to avoid infinite loop
          if (in.read() == -1) {
            long skipped = toSkip - n;
            throw new EOFException("reached end of stream after skipping "
                + skipped + " bytes; " + toSkip + " bytes expected");
          }
          n--;
        } else {
          n -= amt;
        }
      }
    }
  
    public void testAsReadOnlyByteBuffer() {
      ByteBuffer byteBuffer = stringUnderTest.asReadOnlyByteBuffer();
      byte[] roundTripBytes = new byte[referenceBytes.length];
      assertTrue(byteBuffer.remaining() == referenceBytes.length);
      assertTrue(byteBuffer.isReadOnly());
      byteBuffer.get(roundTripBytes);
      assertTrue(classUnderTest + ".asReadOnlyByteBuffer() must give back the same bytes",
          Arrays.equals(referenceBytes, roundTripBytes));
    }
  
    public void testAsReadOnlyByteBufferList() {
      List<ByteBuffer> byteBuffers = stringUnderTest.asReadOnlyByteBufferList();
      int bytesSeen = 0;
      byte[] roundTripBytes = new byte[referenceBytes.length];
      for (ByteBuffer byteBuffer : byteBuffers) {
        int thisLength = byteBuffer.remaining();
        assertTrue(byteBuffer.isReadOnly());
        assertTrue(bytesSeen + thisLength <= referenceBytes.length);
        byteBuffer.get(roundTripBytes, bytesSeen, thisLength);
        bytesSeen += thisLength;
      }
      assertTrue(bytesSeen == referenceBytes.length);
      assertTrue(classUnderTest + ".asReadOnlyByteBufferTest() must give back the same bytes",
          Arrays.equals(referenceBytes, roundTripBytes));
    }
  
    public void testToByteArray() {
      byte[] roundTripBytes = stringUnderTest.toByteArray();
      assertTrue(classUnderTest + ".toByteArray() must give back the same bytes",
          Arrays.equals(referenceBytes, roundTripBytes));
    }
  
    public void testWriteTo() throws IOException {
      ByteArrayOutputStream bos = new ByteArrayOutputStream();
      stringUnderTest.writeTo(bos);
      byte[] roundTripBytes = bos.toByteArray();
      assertTrue(classUnderTest + ".writeTo() must give back the same bytes",
          Arrays.equals(referenceBytes, roundTripBytes));
    }
  
    public void testWriteToShouldNotExposeInternalBufferToOutputStream() throws IOException {
      OutputStream os = new OutputStream() {
        @Override
        public void write(byte[] b, int off, int len) {
          Arrays.fill(b, off, off + len, (byte) 0);
        }
  
        @Override
        public void write(int b) {
          throw new UnsupportedOperationException();
        }
      };
  
      stringUnderTest.writeTo(os);
      assertTrue(classUnderTest + ".writeTo() must not grant access to underlying array",
          Arrays.equals(referenceBytes, stringUnderTest.toByteArray()));
    }
  
    public void testWriteToInternalShouldExposeInternalBufferToOutputStream() throws IOException {
      OutputStream os = new OutputStream() {
        @Override
        public void write(byte[] b, int off, int len) {
          Arrays.fill(b, off, off + len, (byte) 0);
        }
  
        @Override
        public void write(int b) {
          throw new UnsupportedOperationException();
        }
      };
  
      stringUnderTest.writeToInternal(os, 0, stringUnderTest.size());
      byte[] allZeros = new byte[stringUnderTest.size()];
      assertTrue(classUnderTest + ".writeToInternal() must grant access to underlying array",
          Arrays.equals(allZeros, stringUnderTest.toByteArray()));
    }
  
    public void testWriteToShouldExposeInternalBufferToByteOutput() throws IOException {
      ByteOutput out = new ByteOutput() {
        @Override
        public void write(byte value) throws IOException {
          throw new UnsupportedOperationException();
        }
  
        @Override
        public void write(byte[] value, int offset, int length) throws IOException {
          throw new UnsupportedOperationException();
        }
  
        @Override
        public void writeLazy(byte[] value, int offset, int length) throws IOException {
          Arrays.fill(value, offset, offset + length, (byte) 0);
        }
  
        @Override
        public void write(ByteBuffer value) throws IOException {
          throw new UnsupportedOperationException();
        }
  
        @Override
        public void writeLazy(ByteBuffer value) throws IOException {
          throw new UnsupportedOperationException();
        }
      };
  
      stringUnderTest.writeTo(out);
      byte[] allZeros = new byte[stringUnderTest.size()];
      assertTrue(classUnderTest + ".writeToInternal() must grant access to underlying array",
          Arrays.equals(allZeros, stringUnderTest.toByteArray()));
    }
  
    public void testNewOutput() throws IOException {
      ByteArrayOutputStream bos = new ByteArrayOutputStream();
      ByteString.Output output = ByteString.newOutput();
      stringUnderTest.writeTo(output);
      assertEquals("Output Size returns correct result",
          output.size(), stringUnderTest.size());
      output.writeTo(bos);
      assertTrue("Output.writeTo() must give back the same bytes",
          Arrays.equals(referenceBytes, bos.toByteArray()));
  
      // write the output stream to itself! This should cause it to double
      output.writeTo(output);
      assertEquals("Writing an output stream to itself is successful",
          stringUnderTest.concat(stringUnderTest), output.toByteString());
  
      output.reset();
      assertEquals("Output.reset() resets the output", 0, output.size());
      assertEquals("Output.reset() resets the output",
          ByteString.EMPTY, output.toByteString());
    }
  
    public void testToString() throws UnsupportedEncodingException {
      String testString = "I love unicode \u1234\u5678 characters";
      ByteString unicode = ByteString.wrap(testString.getBytes(Internal.UTF_8));
      String roundTripString = unicode.toString(UTF_8);
      assertEquals(classUnderTest + " unicode must match", testString, roundTripString);
    }
  
    public void testCharsetToString() {
      String testString = "I love unicode \u1234\u5678 characters";
      ByteString unicode = ByteString.wrap(testString.getBytes(Internal.UTF_8));
      String roundTripString = unicode.toString(Internal.UTF_8);
      assertEquals(classUnderTest + " unicode must match", testString, roundTripString);
    }
  
    public void testToString_returnsCanonicalEmptyString() {
      assertSame(classUnderTest + " must be the same string references",
          ByteString.EMPTY.toString(Internal.UTF_8),
          ByteString.wrap(new byte[]{}).toString(Internal.UTF_8));
    }
  
    public void testToString_raisesException() {
      try {
        ByteString.EMPTY.toString("invalid");
        fail("Should have thrown an exception.");
      } catch (UnsupportedEncodingException expected) {
        // This is success
      }
  
      try {
        ByteString.wrap(referenceBytes).toString("invalid");
        fail("Should have thrown an exception.");
      } catch (UnsupportedEncodingException expected) {
        // This is success
      }
    }
  
    public void testEquals() {
      assertEquals(classUnderTest + " must not equal null", false, stringUnderTest.equals(null));
      assertEquals(classUnderTest + " must equal self", stringUnderTest, stringUnderTest);
      assertFalse(classUnderTest + " must not equal the empty string",
          stringUnderTest.equals(ByteString.EMPTY));
      assertEquals(classUnderTest + " empty strings must be equal",
          ByteString.wrap(new byte[]{}), stringUnderTest.substring(55, 55));
      assertEquals(classUnderTest + " must equal another string with the same value",
          stringUnderTest, ByteString.wrap(referenceBytes));
  
      byte[] mungedBytes = new byte[referenceBytes.length];
      System.arraycopy(referenceBytes, 0, mungedBytes, 0, referenceBytes.length);
      mungedBytes[mungedBytes.length - 5] = (byte) (mungedBytes[mungedBytes.length - 5] ^ 0xFF);
      assertFalse(classUnderTest + " must not equal every string with the same length",
          stringUnderTest.equals(ByteString.wrap(mungedBytes)));
    }
  
    public void testHashCode() {
      int hash = stringUnderTest.hashCode();
      assertEquals(classUnderTest + " must have expected hashCode", expectedHashCode, hash);
    }
  
    public void testPeekCachedHashCode() {
      assertEquals(classUnderTest + ".peekCachedHashCode() should return zero at first", 0,
          stringUnderTest.peekCachedHashCode());
      stringUnderTest.hashCode();
      assertEquals(classUnderTest + ".peekCachedHashCode should return zero at first",
          expectedHashCode, stringUnderTest.peekCachedHashCode());
    }
  
    public void testPartialHash() {
      // partialHash() is more strenuously tested elsewhere by testing hashes of substrings.
      // This test would fail if the expected hash were 1.  It's not.
      int hash = stringUnderTest.partialHash(stringUnderTest.size(), 0, stringUnderTest.size());
      assertEquals(classUnderTest + ".partialHash() must yield expected hashCode",
          expectedHashCode, hash);
    }
  
    public void testNewInput() throws IOException {
      InputStream input = stringUnderTest.newInput();
      assertEquals("InputStream.available() returns correct value",
          stringUnderTest.size(), input.available());
      boolean stillEqual = true;
      for (byte referenceByte : referenceBytes) {
        int expectedInt = (referenceByte & 0xFF);
        stillEqual = (expectedInt == input.read());
      }
      assertEquals("InputStream.available() returns correct value",
          0, input.available());
      assertTrue(classUnderTest + " must give the same bytes from the InputStream", stillEqual);
      assertEquals(classUnderTest + " InputStream must now be exhausted", -1, input.read());
    }
  
    public void testNewInput_skip() throws IOException {
      InputStream input = stringUnderTest.newInput();
      int stringSize = stringUnderTest.size();
      int nearEndIndex = stringSize * 2 / 3;
      long skipped1 = input.skip(nearEndIndex);
      assertEquals("InputStream.skip()", skipped1, nearEndIndex);
      assertEquals("InputStream.available()",
          stringSize - skipped1, input.available());
      assertTrue("InputStream.mark() is available", input.markSupported());
      input.mark(0);
      assertEquals("InputStream.skip(), read()",
          stringUnderTest.byteAt(nearEndIndex) & 0xFF, input.read());
      assertEquals("InputStream.available()",
                   stringSize - skipped1 - 1, input.available());
      long skipped2 = input.skip(stringSize);
      assertEquals("InputStream.skip() incomplete",
          skipped2, stringSize - skipped1 - 1);
      assertEquals("InputStream.skip(), no more input", 0, input.available());
      assertEquals("InputStream.skip(), no more input", -1, input.read());
      input.reset();
      assertEquals("InputStream.reset() succeded",
                   stringSize - skipped1, input.available());
      assertEquals("InputStream.reset(), read()",
          stringUnderTest.byteAt(nearEndIndex) & 0xFF, input.read());
    }
  
    public void testNewCodedInput() throws IOException {
      CodedInputStream cis = stringUnderTest.newCodedInput();
      byte[] roundTripBytes = cis.readRawBytes(referenceBytes.length);
      assertTrue(classUnderTest + " must give the same bytes back from the CodedInputStream",
          Arrays.equals(referenceBytes, roundTripBytes));
      assertTrue(classUnderTest + " CodedInputStream must now be exhausted", cis.isAtEnd());
    }
  
    /**
     * Make sure we keep things simple when concatenating with empty. See also
     * {@link ByteStringTest#testConcat_empty()}.
     */
    public void testConcat_empty() {
      assertSame(classUnderTest + " concatenated with empty must give " + classUnderTest,
          stringUnderTest.concat(ByteString.EMPTY), stringUnderTest);
      assertSame("empty concatenated with " + classUnderTest + " must give " + classUnderTest,
          ByteString.EMPTY.concat(stringUnderTest), stringUnderTest);
    }
  
    public void testJavaSerialization() throws Exception {
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      ObjectOutputStream oos = new ObjectOutputStream(out);
      oos.writeObject(stringUnderTest);
      oos.close();
      byte[] pickled = out.toByteArray();
      InputStream in = new ByteArrayInputStream(pickled);
      ObjectInputStream ois = new ObjectInputStream(in);
      Object o = ois.readObject();
      assertTrue("Didn't get a ByteString back", o instanceof ByteString);
      assertEquals("Should get an equal ByteString back", stringUnderTest, o);
    }
  }
  